1. Field of the Invention
The present invention relates in general to the field of wireless telecommunications and, more specifically, to a system and method for using plural wireless telecommunications systems to provide accurate position information.
2. Description of the Related Art
Ultra Wide Band (UWB) short-range wireless networks are capable of communicating at very high data rates and, due to UWB's pulse-based protocol, can be used to precisely estimate the range between different objects and, therefore, can be used to determine the location of objects. However, locationing systems utilizing only UWB signals are costly, in terms of both power and size, when compared to systems based on the Institute of Electrical and Electronics Engineers (IEEE) 802.15.4 standard. Systems based on the IEEE 802.15.4 standard, provide extremely low power consumption, low data rate, and low cost (complexity) wireless networking and is capable of providing location estimation with 2 to 3 meters accuracy using Received Signal Strength Indicator (RSSI) methods. Additionally, the location techniques employed on IEEE 802.15.4 networks require a much higher fixed node density because of the comparatively low average coverage range when using IEEE 802.15.4 devices for locationing, which results in higher systems costs. Accuracy using IEEE 802.15.4 devices is reduced significantly when the fixed node separation is greater than 10 meters and is unusable in situations where it is necessary to penetrate walls.
UWB technology can provide precise ranging between objects and has been used in numerous applications, such as asset tracking. UWB systems use a pulse-mode transmitter, which generates and transmits a pulse. The UWB transmitter is significantly smaller in die area and simpler than the UWB receiver and consumes far less power. For example, in a UWB transceiver, the transmitter portion may account for less than two percent of the total die area and may consume less than one percent of the overall power consumption. The UWB receiver, in contrast, is more complicated, is much larger in area, and consumes much more power.
In view of the foregoing, is it apparent that there is a need for a method and system for a cooperative IEEE-802.15.4/UWB system to combine the advantages of both systems to provide a low-cost and low-power precise locationing system.